1. Field of the Invention
The invention relates to a reinforcing support device for a heat sink, more particularly to a secured reinforcing support device which is secured on a computer casing to help bear the mass of a heat sink that is used to absorb and dissipate heat from a central processing unit of a computer.
2. Description of the Related Art
The development of personal computers in recent years has been very fast. With the increase in the functions and operational speed of the computer, the central processing unit is likely to generate large amounts of heat during operation thereof, which can lead to failure of the computer or damage to the electronic components. In order to dissipate the heat generated by the central processing unit during operation, a heat sink is generally mounted on the central processing unit. The same problem exists with other chip devices. In a conventional heat sink mounting structure for a chip device, a heat-conductive gel is used to adhere the heat sink directly onto the chip device, or a mechanical device is used to fasten the heat sink to the chip device. In both cases, the mass or weight of the heat sink is borne by a motherboard on which the chip device is mounted. If the heat sink is relatively heavy, the weight of the heat sink may be a significant load to the motherboard and may result in damage to the motherboard. As the latest Intel Pentium 4 (P4) central processing unit operates at a very high speed, it requires a heat sink with a relatively large heat dissipation area and consequently has a greater weight (about 0.45 kg). In view of this, Intel has required compatible computer casings to be provided with four threaded through holes for passage of threaded fasteners to secure the P4-specific heat sink thereon so that the load of the heat sink can be largely borne by the casing.
However, standard computer casings, such as ATX computer casings, are not provided with such threaded through holes for mounting of the P4-specific heat sink. Therefore, there are available heat sink device mounting structures compatible with the P4-specific heat sink for computer casings not provided with four threaded through holes. One of such structures is shown in FIGS. 1 and 2. The heat sink device as shown includes a heat sink 61 having a plurality of fins 611 in contact with a top surface of a CPU 60 for absorbing the heat generated by the CPU 60. The CPU 60 is mounted on an upper surface of a motherboard 64 via a socket 601 disposed below the CPU 60. The heat sink device further includes a cooling fan 62 secured on an upper surface of the heat sink 61 to help dissipate the heat absorbed by the heat sink 61. The heat sink 61 further has two opposite bottom edges respectively provided with grooves 612. The structure further includes two plastic positioning seats 63, each of which has a fastening rod 631 pivotally mounted at one end thereof and abutting against the corresponding groove 612 to thereby retain the positioning seats 63 at lower edges of the grooves 612 of the heat sink 61. Each positioning seat 63 has a bottom wall formed with two round through holes 632 for passage of two hollow rod members 633, each of which has a lower end forming a split tapered portion 634 that extends downwardly through a corresponding hole 641 in the motherboard 64 to abut against a bottom wall surface of a computer casing 65. Plastic press pins 635 are inserted downwardly into the hollow rod members 633 to thereby expand the split tapered portion 634 such that the hollow rod members 633 are in tight engagement with the walls of the holes 641 in the motherboard 64. As such, the heat sink device can be mounted above the CPU 60 via the positioning seats 63.
Although the above-described heat sink device mounting structure enables the heat sink device to be supported on the bottom wall surface of the computer casing 65, any undue impact or vibration may cause the press pins 635 to slip out of the rod members 633, thereby resulting in loosening of the heat sink device on the CPU 60 or even falling of the heat sink device onto the motherboard 64. Electronic components (not shown) on the motherboard 64 are therefore likely to be damaged.
With reference to FIG. 3, there is also available another type of heat sink device mounting structure in which a relatively heavy iron plate 76 is disposed between and parallel to a motherboard 74 and a bottom wall surface of a computer casing 75. The plate 76 is provided with two pairs of mounting posts 761 projecting from an upper surface thereof for threaded engagement with two pairs of screw bolts 733 extending downwardly through holes 732 in positioning seats 73 of the heat sink device. A plurality of threaded rods 762 extend upwardly from the upper surface of the plate 76 at a peripheral portion. Upper ends of the threaded rods 762 are retained in holes 741 in the motherboard 74. Thus, the plate 76 is suspendedly secured below the motherboard 74, whereas the motherboard 74 is secured on the computer casing 75 through use of screw bolts 742 that engage threaded holes 743 in the motherboard 74 and internally threaded copper posts 751 provided on the bottom wall surface of the computer casing 75. Although the plate 76 helps secure the heat sink device, it is suspended below the motherboard 74 and is not secured directly on the computer casing 75. Thus, the load of the heat sink device and any impact thereon are substantially borne by the motherboard 74.
Therefore, the main object of the present invention is to provide a secured reinforcing support device for a heat sink of a computer.
Accordingly, a secured reinforcing support device according to the present invention helps bear the mass of a heat sink used for absorbing and dissipating heat from a central processing unit of a computer. The computer further includes: a motherboard which has first upper and lower major surfaces opposite to each other in an upright direction, the first upper major surface having a loaded area and a peripheral area surrounding the loaded area, a central processing unit being mounted on the loaded area; a heat sink disposed to be spaced apart from the loaded area in the upright direction and superimposed on the central processing unit to absorb and dissipate heat therefrom; a seat mount disposed to bear and localize the heat sink in the loaded area; and a casing for housing the motherboard, including a bottom major wall surface disposed under the first lower major surface and spaced apart from the first lower major surface in the upright direction to form an accommodation space. The secured reinforcing support device includes a reinforcing support plate, a support post, an inner peripheral wall, a bracing member and a tightening shaft. The reinforcing support plate is adapted to be disposed in the accommodation space. The reinforcing support plate includes second upper and lower major surfaces opposite to each other in the upright direction and adapted to be respectively spaced apart from the first lower major surface and the bottom major wall surface. The second upper major surface includes central and surrounding areas, which are adapted to respectively correspond to and be positioned under the loaded area and the peripheral area. The central area is further adapted to support and be connected to the seat mount through the loaded area. The surrounding area includes a through hole extending downward to communicate with the second lower major surface. The support post includes a lower end adapted to be secured to the bottom major wall surface, and an upper end extending from the lower end upwardly and in the upright direction. The upper end is dimensioned to pass through the through hole so as to abut against the first lower major surface, and has a fastening bore which extends axially and towards the lower end and which defines an axis. The inner peripheral wall is adapted to be disposed in the motherboard to define an insert hole which extends along the axis to communicate the first upper major surface with the first lower major surface. The bracing member includes a joining end disposed to be integrally formed with the reinforcing support plate at the surrounding area, and a clamped portion with a clamped end. The clamped portion extends from the joining end upwardly and in the upright direction such that the clamped end is adapted to be disposed on the first upper major surface and adjacent to the inner peripheral wall. The tightening shaft passes through the insert hole and is disposed to be threadedly engaged with the fastening bore such that when the tightening shaft is in full engagement with the insert hole, the clamped end is forced to abut against the first upper major surface.